Examples of circuit devices are disclosed in Japanese Patent Application No. 7-57830 and Japanese Patent Application No. 8-116178. In the disclosed circuit devices, a plurality of electrical terminals are insert-molded and held inside a dielectric housing. The pads of a circuit board, which are accommodated inside the housing are electrically connected to the terminals. Furthermore, contact sections of the terminals are arranged outside of the housing; together with a portion of the housing, the contact sections engage with a mating connector.
Since the circuit devices described above contain large numbers of parts, the manufacture and assembly of the circuit devices require considerable effort, so that the circuit devices are relatively expensive. A circuit device with a simpler construction which has a smaller number of parts is disclosed in Japanese Patent Application No. 8-185920. In this construction disclosed in this patent application, a circuit board on which electronic parts are mounted is accommodated inside a case, and connector parts which accommodate female terminals that terminate wires are connected to contact pads on the circuit board. In this case, the connector parts are held by being engaged with the case.
However, circuit devices of this type are mounted in automobiles and are used in environments in which violent temperature changes occur. In such cases, the circuit boards contained in such circuit devices undergo deformation as a result of such temperature changes. In the case of a circuit device such as that disclosed in Japanese Patent Application No. 8-185920 described above, there is a danger that faulty contacts between the circuit board and the terminals will be generated by the deformation of the circuit board.
Furthermore, in circuit devices of the type disclosed in Japanese Patent Application No. 8-185920, the circuit board is not stably held inside the case prior to the mounting of the connector parts; as a result, the assembly working characteristics are poor.
Accordingly, the object of the present invention is to provide a circuit device which insures highly reliable electrical connections even when used in environments involving large temperature variations, and which can be easily assembled.